package com.haoyu.number.stack;

import java.util.Scanner;

/**
 * @author 蒿雨
 * @create 2021-11-07 15:25
 */
public class ArrayStackDemo {
    public static void main(String[] args) {
        //测试一把,表示一个栈
        ArrayStack stack = new ArrayStack(4);
        String key = "";
        boolean loop = true;//控制是否退出菜单
        Scanner scanner = new Scanner(System.in);
        while (loop) {
            System.out.println("show:表示显示栈");
            System.out.println("exit:退出程序");
            System.out.println("push:表示添加数据到栈");
            System.out.println("pop:表示从栈取出数据");
            System.out.println("请输入你的选择");
            key = scanner.next();
            switch (key) {
                case "s":
                    stack.list();
                    break;
                case "p":
                    System.out.println("请输入一个数");
                    int value = scanner.nextInt();
                    stack.push(value);
                    break;
                case "pop":
                    try {
                        int res = stack.pop();
                        System.out.printf("出栈的数据是%d\n", res);
                    } catch (Exception e) {
                        e.printStackTrace();
                    }
                    break;
                case "e":
                    scanner.close();
                    loop = false;
                    break;
            }


        }
        System.out.println("程序退出！");

    }
}

//定义一个类，表示栈结构
class ArrayStack {
    private int maxSize;//栈的最大容量
    private int[] stack;//数组模拟栈，数据就放在该数组中
    private int top = -1;//栈顶，初始化-1

    //构造器
    public ArrayStack(int maxSize) {
        this.maxSize = maxSize;
        stack = new int[this.maxSize];
    }

    //栈满
    public boolean isFull() {
        return top == maxSize - 1;
    }

    //判断栈空
    public boolean isEmpty() {
        return top == -1;
    }

    //入栈-push
    public void push(int value) {
        //先判断栈是否满
        if (isFull()) {
            System.out.println("栈满");
            return;
        }
        top++;
        stack[top] = value;
    }

    //出栈,将栈顶的数据返回
    public int pop() {
        if (isEmpty()) {
            System.out.println("栈空了");
            throw new RuntimeException("栈空，没有数据");
        }
        int value = stack[top];
        top--;
        return value;
    }

    //显示栈的情况,遍历时，需要从栈顶开始显示数据
    public void list() {
        if (isEmpty()) {
            System.out.println("没有数据，无法遍历");
            return;
        }
        for (int i = top; i >= 0; i--) {
            System.out.printf("stack[%d]=%d\n", i, stack[i]);
        }
    }
}
